U.S. patent number 4,919,845 [Application Number 07/378,447] was granted by the patent office on 1990-04-24 for phosphate-free detergent having a reduced tendency towards incrustation.
This patent grant is currently assigned to Henkel Kommanditgesellschaft auf Aktien. Invention is credited to Hans Andree, Gertrud Nienhaus, Guenther Vogt.
United States Patent |
4,919,845 |
Vogt , et al. |
April 24, 1990 |
**Please see images for:
( Certificate of Correction ) ** |
Phosphate-free detergent having a reduced tendency towards
incrustation
Abstract
A detergent composition containing by weight (a) from 5 to 35%
of an anionic or nonionic surfactant, (b) from 10 to 40% of finely
crystalline zeolite, (c) from 4 to 20% of alkali metal silicate or
carbonate and from 0.1 to 5% of (d) aminoalkanephosphonate or (d2)
copolymer of (meth)acrylic acid and maleic acid and (e) from 5 to
80% of other detergent constituents is considerably improved in
regard to its incrustation-inhibiting properties if it additionally
contains (f) from 0.05 to 1% (based on the free acid) of
1-hydroxyethane-1,1-diphosphonic acid in the form of its alkali
metal salt. The weight ratio of (d1) to (f) is from 3:1 to 1:6 and
of (d2) to (f) is from 40:1 to 2:1.
Inventors: |
Vogt; Guenther (Toenisvorst,
DE), Andree; Hans (Leichlingen, DE),
Nienhaus; Gertrud (Duesseldorf, DE) |
Assignee: |
Henkel Kommanditgesellschaft auf
Aktien (Duesseldorf, DE)
|
Family
ID: |
6328146 |
Appl.
No.: |
07/378,447 |
Filed: |
July 7, 1989 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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195996 |
May 19, 1988 |
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Foreign Application Priority Data
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May 21, 1987 [DE] |
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3717227 |
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Current U.S.
Class: |
510/356; 252/179;
252/180; 510/276; 510/305; 510/306; 510/307; 510/313; 510/357;
510/361; 510/469; 510/507 |
Current CPC
Class: |
C11D
3/128 (20130101); C11D 3/361 (20130101); C11D
3/364 (20130101); C11D 3/3761 (20130101) |
Current International
Class: |
C11D
3/36 (20060101); C11D 3/12 (20060101); C11D
003/08 (); C11D 003/12 (); C11D 003/30 (); C11D
003/36 () |
Field of
Search: |
;252/109,110,131,135,140,155,174.14,174.16,174.24,174.25,179,180,539,540,526 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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026529 |
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Aug 1981 |
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EP |
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0124913 |
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Nov 1984 |
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EP |
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3526405 |
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May 1987 |
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DE |
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2097419A |
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Nov 1982 |
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GB |
|
Primary Examiner: Albrecht; Dennis
Attorney, Agent or Firm: Szoke; Ernest G. Jaeschke; Wayne C.
Grandmaison; Real J.
Parent Case Text
This application is a continuation of application Ser. No.
07/195,996, filed 5/19/88, now abandoned.
Claims
We claim:
1. A detergent composition consisting of:
(a) from about 5 to about 35% by weight of at least one
water-soluble surfactant selected from the group consisting of an
anionic and a nonionic compound,
(b) from about 10 to about 40% by weight of a finely crystalline
synthetic zeolite NaA,
(c) from about 4 to about 20% by weight of a washing alkali
selected from the group consisting of an alkali metal silicate and
carbonate,
(d) the following compounds in the form of their alkali metal salt;
based on free acid,
(d1) from about 0.1 to about 1% by weight of an aminoalkane
polyphosphonic acid,
(d2) from about 0.5 to about 5% by weight of a linear polymer or
copolymer of acrylic acid or methacrylic acid and maleic acid,
and
(e) from about 0.5 to about 1% by weight, based on free acid, of
1-hydroxyethane-1,1-diphosphonate in the form of its alkali metal
salt, with the proviso that the ratio by weight of component
(d1):(e) is from about 40:1 to about 2:1, all weights being based
on the weight of said detergent composition.
2. A detergent composition as in claim 1 wherein said component
(d1) is selected from the group consisting of ethylenediamine
tetramethylene phosphonate, diethylenetriamine pentamethylene
phosphonate, and higher homologs thereof.
3. A detergent composition as in claim 1 wherein said component
(d2) is selected from the group consisting of polyacrylate,
polymethacrylate, and a copolymer of acrylic acid with maleic
acid.
4. A detergent composition as in claim 3 wherein said copolymer
comprises from about 50 to about 90% by weight of acrylic acid and
from about 50 to about 10% by weight of maleic acid and has a
molecular weight of between about 2,000 and about 200,000.
5. A detergent composition as in claim 1 containing component (d1)
and component (d2) in a weight ratio of from about 1:1 to about
1:30.
6. A detergent composition as in claim 1 containing component (d1)
and component (e) in a weight ratio of from about 2:1 to about
1:4.
7. A detergent composition as in claim 1 containing component (d2)
and component (e) in a weight ratio of from about 20:1 to about
4:1.
8. A detergent composition as in claim 1 wherein components (d1),
(d2) and (e) are present in the form of the sodium salts.
9. A detergent composition as in claim 1 wherein said anionic
compound is selected from a sulfonate and a sulfate.
10. A detergent composition as in claim 1 wherein said nonionic
compound is a polyglycol ether derivative.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a phosphate-free detergent composition
having a reduced tendency towards fabric incrustation, and more
particularly, to such a composition containing a combination of an
aminoalkane polyphosphonate, a polymeric carboxylic acid, and a
hydroxyalkane diphosphonate.
2. Discussion of Related Art
Phosphate-free detergents containing finely crystalline
aluminosilicates as a phosphate substitute, sodium carbonate or
sodium silicates as washing alkali, and polyanionic compounds from
the class of aminoalkane polyphosphonic acids and homo- or
copolymer polycarboxylic acids derived from acrylic acid,
methacrylic, maleic acid and olefinically unsaturated,
copolymerizable compounds are known. The phosphonic acids or salts
thereof which are used preferably include ethylenediamine
tetramethylene phosphonate, generally in the form of their sodium
salts. Preferred polymeric carboxylic acids include copolymers of
maleic acid with vinylmethylethers and, in particular, copolymers
of maleic acid with acrylic acid in a ratio of 1:5 to 1:1 having a
molecular weight of from 10,000 to 150,000. These polyacids are
also normally present in the detergents as sodium salts. The
quantities of aminoalkane phosphonates used are normally 0.1 to 1%
by weight and the quantities of copolymers 3 to 6% by weight, based
on the detergents. However, the complexing and
precipitation-retarding properties (so-called threshold effect) of
these additives are generally not good enough to limit the
formation of fiber incrustations to the required extent because it
has been found that the incrustations increase considerably when
the fabrics are repeatedly washed with hard water, and can
ultimately assume undesirable proportions. This increase in the
incrustations is reflected in increasing hardening and
discoloration (graying) of the fabric and may be quantitatively
evaluated by determination of the fabric ash.
Accordingly, there exists the problem of reducing this tendency to
form such incrustations.
DESCRIPTION OF THE INVENTION
Other than in the operating examples, or where otherwise indicated,
all numbers expressing quantities of ingredients or reaction
conditions used herein are to be understood as modified in all
instances by the term "about".
The present invention, which solves this problem, relates to as
detergent composition comprising:
(a) from 5 to 35% by weight of at least one water-soluble
surfactant selected from the group consisting of an anionic and a
nonionic compound,
(b) from 10 to 40% by weight of a finely crystalline synthetic
zeolite NaA,
(c) from 4 to 20% by weight of a washing alkali selected from the
group consisting of an alkali metal silicate and carbonate,
(d) from 0.1 to 5% by weight, based on free acid, of at least one
of the following compounds in the form of its alkali metal
salt;
(d1) an aminoalkane polyphosphonic acid,
(d2) a linear polymer or copolymer of acrylic acid or methacrylic
acid and maleic acid,
(e) from 5 to 80% by weight of other detergent constituents,
characterized in that the detergent composition contains
(f) from 0.5 to 1% by weight, based on free acid, of
1-hydroxyethane-1,1-diphosphonate in the form of its alkali metal
salt, with the proviso that the ratio by weight of the component
(d1):(f) is from 3:1 to 1:6 and that of component (d2):(f) is from
40:1 to 2:1, all weights being based on the weight of the detergent
composition.
By phosphate-free is meant a detergent which contains less than
0.1% inorganically bound phosphorus.
The crucial feature of the invention is the joint use of the
aminoalkane polyphosphonate or polymeric carboxylic acid or
mixtures thereof mentioned under (d) with the hydroxyalkane
diphosphonate mentioned under (f). Although the use of
hydroxyalkane phosphonate (component f) in a detergent and cleaning
preparation has been known for some time, this compound has not
been used in modern phosphate-free detergents since the discovery
of the aminoalkane phosphonates (d1) and the polymers according to
(d2) because the hydroxyalkane phosphonate is known to have a very
much lower sequestering power than the aminoalkane phosphonates
according to (d1) and, in addition, has virtually no threshold
properties comparable with the polymers according to (d2).
Accordingly, it was extremely surprising to find that the joint use
of the phosphonates (d1) and (f) provides for a considerably
improved incrustation-inhibiting effect in relation to the sole use
of only one of the two phosphonate types. The same applies to the
joint use of the polymers according to (d2) and the component (f).
The synergistic effect of the combination consisting of all three
components is particularly pronounced.
Preferred salts of aminoalkane phophonic acids for component (d1)
are ethylenediamine tetramethylene phosphonate (EDTMP),
diethylenetriamine pentamethylene phosphonate (DTPMP) and higher
homologs thereof. They are preferably used in the form of their
neutralized sodium salts, for example as the hexasodium salt of
EDTMP or as the hepta- or octa-sodium salt of DTPMP. They are
present in the detergent composition in a quantity, expressed as
free acid, of preferably from 0.1 to 1% by weight, and more
preferably from 0.1 to 0.5% by weight, based on the weight of the
composition.
Suitable (co)polymeric polycarboxylates (component d2) include
polyacrylates, polymethacrylates and, in particular, copolymers of
acrylic acid with maleic acid, preferably those containing 50% to
90% by weight of acrylic acid and 50% to 10% by weight of maleic
acid. The molecular weight of the homopolymers is generally between
1000 and 100,000 and that of the copolymers between 2000 and
200,000 and preferably betwen 50,000 and 120,000, based on the free
acid. A particularly preferred acrylic acid/maleic acid copolymer
has a molecular weight of from 50,000 to 100,000.
Suitable, albeit less preferred, compounds of this class include
copolymers of acrylic acid or methacrylic acid with vinyl ethers,
such as vinylmethylether, in which the acid makes up at least 50%.
It is also possible to use polyacetal carboxylic acids of the type
described, for example, in U.S. Pat. Nos. 4,144,226 and 4,146,495
and obtained by polymerization of esters of glycolic acid,
introduction of stable terminal groups and hydrolysis to the sodium
or potassium salts. Polymeric acids obtained by polymerization of
acrolein and Canizzaro disproportionation of the polymer with
strong alkalis are also suitable. The consist essentially of
acrylic acid units and vinyl alcohol units or acrolein units.
The (co)polymeric polycarboxylic acid content of the detergent
composition, based on free acid (component d2), is preferably 0.5
to 5% by weight and more preferably 1 to 4% by weight.
The detergent composition may contain components (d1) and (d2)
either individually or even together, preferably together. Where
components (d1) and (d2) are present together, the mixing ratio of
(d1) to (d2) is, for example, from 1:1 to 1:30 and preferably from
1:5 to 1:20, by weight.
The 1-hydroxyethane-1,1-diphosphonate (component f) is also
preferably present in the form of the sodium salt. The disodium
salt shows a neutral reaction and the tetrasodium salt an alkaline
reaction (pH 9). It is present in a quantity, based on acid, of
from 0.05 to 1% by weight, preferably from 0.1 to 0.7% by weight
and more preferably from 0.1 to 0.5% by weight. The ratio by weight
of (d1) to (f) is from 3:1 to 1:6 and preferably from 2:1 to 1:4,
while the ratio by weight of (d2) to (f) is from 40:1 to 2:1 and
preferably from 20:1 to 4:1.
The detergent composition according to the invention contains
anionic or nonionic surfactants as further constituents (component
a). These include soaps, anionic surfactants of the sulfonate and
sulfate type and also nonionic compounds, for example, from the
class of polyglycol ether derivatives. The detergent composition
contains from 5 to 35% by weight and preferably from 8 to 20% by
weight of component (a), based on the weight of the detergent
composition.
Suitable soaps include those derived from natural or synthetic,
saturated or monounsaturated C.sub.12 -C.sub.22 fatty acids. Soap
mixtures derived from natural fatty acids, for example coconut oil,
palm kernel oil or tallow fatty acids, are particularly suitable.
Preferred soap mixtures are those of which 50 to 100% by weight
consists of saturated C.sub.12 -C.sub.18 fatty acid soaps and 0 to
50% by weight of oleic acid soap.
Suitable surfactants of the sulfonate type include linear
alkylbenzenesulfonates (C.sub.9 -C.sub.13 alkyl) and olefin
sulfonates, i.e. mixtures of alkene- and hydroxyalkanesulfonates
and also disulfonates of the type obtained, for example from
C.sub.12 -C.sub.18 monoolefins containing a terminal or internal
double bond by sulfonation with gaseous sulfur trioxide and
subsequent alkaline hydrolysis of the sulfonation products. Other
suitable surfactants of the sulfonate type include alkanesulfonates
of the type obtainable from C.sub.12 -C.sub.18 alkanes by
sulfochlorination or sulfoxidation and subsequent hydrolysis or
neutralization and also .alpha.-sulfofatty acids and esters
thereof, for example the .alpha.-sulfonated hydrogenated coconut
oil, palm kernel oil or tallow fatty acids and their methyl or
ethyl esters and mixtures thereof.
Suitable surfactants of the sulfate type include the sulfuric acid
monoesters of primary alcohols of natural and synthetic origin,
i.e. of fatty alcohols such as, for example, coconut fatty
alcohols, tallow fatty alcohols, oleyl alcohol, lauryl, myristyl,
palmityl or stearyl alcohol, or the C.sub.10 -C.sub.18 oxoalcohols
and also the sulfuric acid esters of secondary alcohols of the same
chain length. The sulfuric acid monoesters of aliphatic primary
alcohols ethoxylated with 1 to 6 moles of ethylene oxide and
ethoxylated secondary alcohols or alkyl phenols are also suitable.
Sulfatized fatty acid alkanolamides and sulfatized fatty acid
monoglycerides are also suitable.
Preference is attributed to surfactants containing sulfonate groups
and, among these, to alkylbenzenesulfonates, .alpha.-sulfofatty
acid ester salts and .alpha.-sulfofatty acid ester di-salts. The
anionic surfactants are normally present in the form of their
sodium salts. The quantity in which they are present, based on the
detergent compositions, is generally from 2 to 15% by weight, and
preferably from 5 to 12% by weight.
Suitable nonionic surfactants include adducts of 2 to 20, and
preferably 3 to 15, moles of ethylene oxide with 1 mole of a
compound essentially containing 10 to 20 carbon atoms selected from
the group consisting of alcohols and alkylphenols. Of particular
importance are the adducts of 7 to 15 moles of ethylene oxide with
primary alcohols, for example with coconut or tallow fatty
alcohols, with oleyl alcohol, with oxoalcohols, or with secondary
alcohols containing 8 to 18 and preferably 12 to 18 carbon atoms
and also with mono- or dialkylphenols containing 6 to 14 carbon
atoms in the alkyl radicals. In addition to these water-soluble
nonionics, however, water-insoluble or substantially
water-insoluble polyglycol ethers containing 2 to 6 ethylene glycol
ether groups in the molecule may also be used, particularly where
they are used together with water-soluble nonionic or anionic
surfactants. Other suitable nonionic surfactants include alkyl
glycosides and alkyl polyglycosides wherein the alkyl group
contains 8 to 18 and preferably 10 to 16 carbon atoms. The quantity
of nonionic surfactant or mixture of nonionic surfactants in the
detergent composition is preferably from 3 to 10% by weight and
more preferably from 3 to 7% by weight, based on the weight of the
detergent composition.
Component (b) consists of finely crystalline, synthetic
water-containing zeolites of the NaA type which have a calcium
binding power of 100 to 200 mg CaO/g (as defined in German Patent
22 24 837). Their particle size is normally in the range from 1 to
10 .mu.m. The quantity of component (b) is from 10 to 40% by weight
and preferably from 12 to 25% by weight, based on the weight of the
detergent composition.
Suitable washing alkalis (component c) include alkali metal
silicates, particularly sodium silicates having the composition
Na.sub.2 O:SiO.sub.2 =1:1 to 1:3.5 and preferably 1:2 to 1:3.35.
Their quantity in the detergent composition may be from 1 to 8% by
weight and is preferably from 2 to 5% by weight, based on the
weight of the detergent composition. The sodium silicate improves
the particle stability and particle structure of the powder-form or
granular detergent composition and has a favorable effect on its
dispensing and dissolving behavior in automatic washing machines.
It also has an anticorrosive effect and improves detergency.
Although it was known that relatively large contents, i.e. more
than 2 to 3% by weight, of alkali metal silicates in
zeolite-containing detergent compositions lead to irreversible
agglomeration of the zeolite particles which are deposited on the
fabrics and can increase their ash value and impair their
appearance, it has surprisingly been found that this adverse effect
is largely eliminated by the combination of components (d) and (f)
according to the invention and that the content of sodium silicate,
desirable for the reasons mentioned, can be increased without any
of the above-mentioned disadvantages.
The washing alkali (component c) may also be sodium carbonate whose
content in the detergent composition may be up to 15% by weight and
is preferably from 2 to 12% by weight and more preferably from 5 to
10% by weight. The total quantity of sodium silicate and sodium
carbonate comprises 4 to 20% by weight, preferably from 5 to 15% by
weight and more preferably from 7 to 12% by weight, based on the
weight of the detergent composition.
The other detergent constituents (component e), of which the
content in the detergent composition is from 5 to 80% by weight and
preferably from 10 to 50% by weight, based on the weight of the
detergent composition, include redeposition inhibitors (soil
suspending agents), bleaches, bleach activators, optical
brighteners, foam inhibitors, enzymes, fabric softeners, dyes and
perfumes and also neutral salts and water.
The detergent and cleaning preparations may contain as part of this
component (c) redeposition inhibitors which keep the soil detached
from the fibers suspended in the wash liquor and thus prevent its
redeposition. Suitable redeposition inhibitors include
water-soluble, generally organic, colloids such as, for example,
the water-soluble salts of polymeric carboxylic acids, glue,
gelatin, salts of ether carboxylic acids or ether sulfonic acids of
starch or cellulose, or salts of acidic sulfuric acid esters of
cellulose or starch. Water-soluble polyamides containing acidic
groups are also suitable for this purpose. It is also possible to
use soluble starch preparations and other starch products than
those mentioned above, such as for example degraded starch,
aldehyde starches, etc. Polyvinyl pyrrolidone may also be used.
Carboxymethyl cellulose (Na salt), methyl cellulose and mixtures
thereof are preferably used. The quantity of these compounds in the
detergent composition is generally from 0.2 to 2% by weight and
preferably from 0.5 to 1.5% by weight, based on the weight of the
detergent composition.
Of the compounds yielding H.sub.2 O.sub.2 in water which are used
as bleaches, sodium perborate tetrahydrate (NaBO.sub.2.H.sub.2
O.sub.2.3H.sub.2 O) and the monohydrate (NaBO.sub.2.H.sub.2
O.sub.2) are of particular importance. However, it is also possible
to use other H.sub.2 O.sub.2 -yielding borates, for example
perborax Na.sub.2 B.sub.4 O.sub.7.4H.sub.2 O.sub.2. These compounds
may be completely or partly replaced by other active oxygen donors,
more especially peroxyhydrates, such as peroxycarbonates (Na.sub.2
CO.sub.3.1.5H.sub.2 O.sub.2), peroxypyrophosphates, citrate
perhydrates, urea-H.sub.2 O.sub.2 or melamine-H.sub.2 O.sub.2
compounds, and also by H.sub.2 O.sub.2 -yielding peracidic salts or
peracids, such as perbenzoates, peroxyphthalates, diperazelaic acid
or diperdodecanedioic acid.
To obtain an improved bleaching effect at washing temperatures
below 80.degree. C. and more especially in the range from
40.degree. to 60.degree. C., bleach activators may be incorporated
in the detergent composition. Examples of bleach activators include
N-acyl and O-acyl compounds which form organic peracids with
H.sub.2 O.sub.2, preferably N,N.sup.1 -tetraacylated diamines, such
as N,N,N.sup.1,N.sup.1 -tetraacetyl ethylenediamine, also
carboxylic anhydrides, such as benzoic anhydride and phthalic
anhydride, and esters of polyols, such as glucose pentaacetate.
The detergent composition may contain in particular derivatives of
diaminostilbene disulfonic acid and alkali metal salts thereof as
optical brighteners for cotton. Suitable constituents of this type
include, for example, salts of 4,4.sup.1
-bis-(2-anilino-4-morpholino-1,3,5-triazin-6-ylamino)-stilbene-2,2.sup.1
-disulfonic acid or compounds of similar structure which contain a
diethanolamino group, a methylamino group or a 2-methoxyethylamino
group instead of the morpholino group. Suitable brighteners for
polyamide fibers include those of the 1,3-diaryl-2-pyrazoline type,
for example the compound
1-(p-sulfamoylphenyl)-3-(p-chlorophenyl)-2-pyrazoline. Brighteners
of the substituted 4,4.sup.1 -distyryldiphenyl type, for example
the compound 4,4.sup.1 -bis-(4-chloro-3-sulfostyryl)-diphenyl, may
also be present. Mixtures of the above-mentioned brighteners may
also be used.
Suitable enzymes include those from the class of proteases, lipases
and amylases and mixtures thereof. Enzymatic agents obtained from
bacterial strains or fungi, such as Bacillus subtilis, Bacillus
licheniformis and Streptomyces griseus are particularly suitable.
The enzymes may be adsorbed onto carriers and/or embedded in
shell-forming substances to protect them against premature
decomposition.
Suitable foam inhibitors include organopolysiloxanes and mixtures
thereof with microfine, optionally silanized silica, paraffins,
waxes, microcrystalline waxes and mixtures thereof with silanized
silica. Bis-acylamides derived from C.sub.12 -C.sub.20 fatty acids
and C.sub.2 -C.sub.6 diamines and from C.sub.12 -C.sub.20
alkylamines and C.sub.2 -C.sub.6 dicarboxylic acids may also be
used. It is also of advantage to use mixtures of different foam
inhibitors, for example mixtures of silicones and paraffins or
waxes or of bisacylamides and paraffins or waxes. The foam
inhibitors are preferably bound to a granular water-soluble or
water-dispersible carrier material.
Suitable fabric-softening additives include layer silicates from
the class of bentonites and smectites, for example those according
to German Patent 23 34 899 and European Patent 26 529. Also
suitable are synthetic finely-divided layer silicates having a
smectite like crystal phase and a reduced swelling power
corresponding to the following formula
wherein M is sodium, optionally sodium together with lithium, with
the proviso that the molar ratio of Na to Li is at least 2, a=0.05
to 0.4, b=0 to 0.3, c=1.2 to 2 and n=0.3 to 3, (H.sub.2 O).sub.n
representing the water bound in the crystal phase. Other suitable
fabric softeners include synthetic layer silicates which, after
suspension in water (16.degree. Gh, room temperature), have a
swelling power, determined as the quotient of the sediment volume
(V.sub.s /total volume (V) after treatment with excess soda
solution, careful washing and 20 hours after suspension in 9 parts
by weight water/1 part by weight layer silicate, of V.sub.s /V=less
than 0.6 and, more especially, less than 0.4; and synthetic layer
silicates which have a mixed crystal structure comprising
structure-determining saponite- and/or hectorite-like crystal
phases which are irregularly permeated by crystalline alkali metal
polysilicate. Layer silicates such as these are described in detail
in German Patent 35 26 405. The content of layer silicates may be,
for example, from 5 to 20% by weight, based on the weight of the
detergent composition.
The detergent composition may be produced in a conventional manner,
i.e. by spray drying of the constituents which are stable under
spray-drying conditions and subsequent incorporation of the
heat-sensitive components, such as bleaches, enzymes, perfumes and
foam inhibitors. Other suitable processes include granulation of
the consituents, in which case water, salt solutions, polymer
solutions and/or nonionic surfactants may be used as the
granulation liquid. Of particular value is the discovery that,
despite the presence of zeolites, the alkali metal silicate content
may be increased to more than 2.5 to 3% by weight without any
danger of increased ash formation, so that the particle strength
and pourability of the final granular powder may be increased
because the addition of HEDP (component f) counteracts ash
formation.
EXAMPLES
Granular detergent compositions having the formulations shown below
were prepared and tested. The constituents shown in 1st to 9th
place and most of the sodium sulfate were mixed to form an aqueous
slurry and spray-dried in a test tower. The perborate, the bleach
activator and granulates were subsequently incorporated in the
spray-dried product. The quantities are in % by weight.
7.0 Na dodecyl benzenesulfonate
1.5 Na tallow soap
6.5 C.sub.12 -C.sub.18 fatty alcohol+3-5 moles ethylene oxide
25.0 zeolite NaA
10.0 sodium carbonate
2.5 Na silicate (Na.sub.2 O:SiO.sub.2 =1:3.3)
0.8 cellulose ether
0.2 optical brightener
5.0 phosphonate/copolymer/Na sulfate mixture
25.0 Na perborate tetrahydrate
2.0 tetraacetyl ethylenediamine
0.5 enzyme granulate
0.5 silicone foam inhibitor granulate
balance sodium sulfate, water
Testing was carried out under near-practical conditions in domestic
washing machines. To this end, the machines were loaded with 3.5 kg
of normally soiled domestic washing (bed linen, table linen,
underwear) and 0.5 kg of test fabrics in the form of strips of
standardized cotton fabric (Wascheforschungsanstalt Krefeld),
nettle, knitted fabric (cotton tricot) and terry cloth. Washing
conditions: tapwater at 16.degree. C. (equivalent to 160 g
CaO/liter), prewash cycle 5 g/l at 15.degree. to 30.degree. C.,
main wash cycle 7.5 g/l at 25.degree. to 92.degree. C. (heating
times 15 mins., 15 mins. at 92.degree. C.), wash liquor ratio (kg
washing per liter wash liquor) in main wash cycle 1:4, 5 rinses
with tapwater, spin-drying and tumbler drying. After 50 wash
cycles, the ash content of the fabric samples was quantitatively
determined.
In Table 1 below, EDTMP stands for the hexasodium salt of
ethylenediamine tetramethylenephosphonic acid (1 g salt
corresponding to 0.77 g free acid), HEDP for the tetrasodium salt
of 1-hydroxy-1,1-ethane diphosphonic acid (1 g salt corresponding
to 0.7 g free acid), AMC for the sodium salt of a copolymer of
acrylic acid and maleic acid in a molar ratio of 4:1, molecular
weight 70,000, pH value 9 (partially neutralized, 1 g salt
corresponding to approx. 0.82 g free acid). The quantities of the
salts used are shown in % by weight (the amount expressed as free
acid is shown beneath in brackets). The balance to 5% by weight is
made up by sodium sulfate.
In the absence of the 3 components (d1), (d2) and (f), the average
value of the ash content determined among all the fabric samples
was 9.2% by weight after 50 washes. The result is shown as the
percentage change in the ash content (+=increase, -=decrease) in
relation to that standard.
The lowest ash values (greatest reduction in relation to the
standard) are obtained in accordance with Examples 1 to 3 by the
combination of components (d1), (d2) and (f). However, the
2-component combinations of Examples 5 to 9 also lead to a distinct
ash reduction compared with the combinations described in the
following comparison tests.
The following known complexing agents
NTA (trisodium salt of nitrilotriacetic acid),
EDTA (tetrasodium salt of ethylenediamine tetraacetic acid) and
DTPMP (heptasodium salt of diethylenetriamine pentamethylene
phosphonic acid)
were additionally investigated in the comparison tests.
The quantities in Table 2 relate to the salts. The balance to 5%
consists of sodium sulfate. The test S represents the standard.
The results show that even small additions of HEDP to the detergent
composition lead to a considerable reduction in fabric
incrustation. A corresponding increase in the proportions of
aminopolyphosphonic acids (EDTMP and DTPMP) or of copolymers does
not produce a comparable reduction in the ash values. Replacement
by other complexing agents (EDTA, NTA) has no beneficial effect or
even increases incrustation.
EXAMPLE 10
In the detergent composition according to test A (Table 2), the
sodium silicate content was increased in increments to 3.7, 5 and
6% by weight at the expense of the sodium sulfate content, the ash
values increasing by 35%, 37% and 38% in relation to the standard.
Providing 0.4% HEDP (Na salt) was added, there was no increase in
the ash values. A corresponding increase in the EDTMP content did
not produce a comparable improvement, i.e. the ash values increased
by 22%.
TABLE 1 ______________________________________ Ash Example EDTMP
(%) HEDP (%) AMC (%) (% change)
______________________________________ 1 0.22 0.22 4.0 -55 (0.17)
(0.154) (3.2) 2 0.22 0.4 4.0 -61 (0.17) (0.28) (3.2) 3 0.22 0.4 3.0
-65 (0.17) (0.28) (2.7) 5 0.20 0.6 -- -50 (0.154) (0.42) -- 6 0.6
0.20 -- -48 (0.46) (0.14) 7 -- 0.22 4.0 -44 (0.154) (3.2) 8 -- 0.4
4.0 -53 (0.28) (3.2) 9 -- 0.4 5.0 -49 (0.28) (4.0)
______________________________________
TABLE 2 ______________________________________ EDTMP AMC DETMP NTA
EDTA Ash Test % % % % % (% change)
______________________________________ S 0.22 -- -- -- -- -- A 0.22
4.0 -- -- -- -34 B 0.45 4.0 -- -- -- -41 C 0.60 4.0 -- -- -- -44 D
0.22 5.0 -- -- -- -28 E -- 5.0 -- -- -- +15 F -- 4.0 0.6 -- -- -3 G
-- 4.0 -- 1.0 -- +20 H 0.22 -- -- -- 0.20 .+-.0
______________________________________
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